页岩气压裂返排液膜蒸馏处理

页岩气开采过程中产生的压裂返排液处理难度大是其开采成本较高的主要原因之一。对长宁地区返排液进行了理化指标检测,用PTFE双向拉伸微孔膜搭建了平板型真空膜蒸馏装置,保持真空侧绝对压力为10KPa,探究了雷诺数及料液温度等主要操作条件对膜蒸馏过程的影响。结果表明该PTFE双向拉伸微孔膜蒸馏能有效处理这类页岩气压裂返排液,料液温度对膜通量影响显著。在料液温度335K,流动雷诺数为800的条件下,膜通量能达到30.3kg.m~(-2).h~(-1);产水的电导率均小于20μS.cm~(-1),计算脱盐率大于99.9%,产水COD均小于15mg.L~(-1),去除率达到93%,产水达到一级国标。     

竖直管降膜流动的CFD分析

建立了竖直管降膜流动的二维模型,采用RNG κ-ε湍流模型、VOF模型,对管内的降膜流动进行了CFD研究,得到了稳定前后的液膜、速度分布。研究发现,沿管长方向的流动稳定后,依次分为平稳区、小幅波动区、大幅震荡区,在给定流速下平稳区、波动区膜厚为0.63 mm、0.23~1.5 mm。在平稳区不同位置处液膜流速在膜厚方向变化一致,沿管长有增大趋势,最大速度在膜内,流动稳定后分布变化不大。最后将模拟得到的膜厚与学者数据进行了对比,结果可靠。     

膜生物反应器 CCCF 过程中酵母细胞生长特性研究

渗透汽化膜生物反应器CCCF过程乙醇发酵中酵母细胞的生长表现出五个不同的阶段,即：快速生长期、乙醇抑制期、二次生长期、平衡期和衰亡期。采用摇瓶实验对发酵副产物（主要为有机酸和甘油）的抑制行为进行检测,结果表明随着副产物浓度的增加,抑制作用越来越强,细胞生长表现出较长的迟滞期和较低的细胞浓度。当副产物浓度达到膜生物反应器中发酵后期的浓度时,细胞的比生长速率和得率仅分别为0．061和0．024。     

基于分离效率的卧螺离心机CFD分析

从分离效率的角度对卧式螺旋卸料离心机转鼓内的流场进行数值分析.通过剖析推料螺旋与转鼓溢流堰的结构特点可知,转鼓内流体在轴向为薄层流动,在径向由于涡流产生向内流动导致颗粒上浮,这两者对离心机分离效率有决定性的影响.结合CFD数值分析和颗粒的Stokes沉降运动关系,提出将薄层流动与上浮临界粒度应用于离心机分离能力计算的理论和方法.文章通过定义沉降粒度和上浮临界粒度,进一步把分离能力计算与分离效率相关联,使该方法更接近离心机分离工艺的实际情况.通过对工业中典型离心机进行实例计算,证明了该方法的可行性和准确性.     

硅橡胶复合膜用于渗透蒸发的膜传质动力学(Ⅱ)膜内的扩散传质

The pervaporation of organics from dilute aqueous solution through a novel plate composite silicone rubber membrane was investigated. The measured and derived data indicated that the composite membrane possessed very high permeation flux and stable selectivity for dilute organic aqueous solution. Based upon the well- known resistance-in- series model, diffusive mass transfer behavior in membrane was investigated by calculation from the measured data with different skin layer thickness of membranes. The experimental results showed that the diffusive mass transfer coefficient conformed to Arrhenius correlation with temperature and was independent of the flow status. The diffusivities of the given alcohols in membrane had an order of magnitude 10 m-10·s-1 at a wider range of temperature, which is similar to those reported in literatures.     

PDMS复合膜从发酵液中渗透汽化回收乙醇

The pervaporation behavior of fermentation broth was investigated experimentally and compared with those started with ethanol mixtures. Ethanol was produced by Saccharomyces cerevisiae utilizing technical grade glucose and recovered by pervaporation using a composite polydimethylsiloxane (PDMS) membrane prepared in our laboratory. Ethanol concentration in fermentation broth decreased to a relatively low level when pervaporation was coupled with fermentation. The more active cells appeared in the fermentation broth, the better the membrane performance was.     

适合硅橡胶膜生物反应器乙醇发酵的酵母选育（Ⅰ）

从水果中筛选出一株野生型酵母S3,并将其运用于膜牛物反应器封闭循环乙醇发酵.运用酵母S3进行了3次摇瓶发酵实验,得到细胞浓度、乙醇产率以及葡萄糖转化率的最大值分别为:5.37g/L,1.90g/(L·h),87.9%;将S3菌株接人膜牛物反应器封闭循环发酵系统,进行了524.4 h的封闭循环发酵实验,整个发酵过程乙醇产率为1.48g/(L·h).葡萄糖消耗速率为3.55g/(L·h),发酵结束时,细胞存活率为30%,葡萄糖转化率为81.4%,均高于菌株SO的发酵结果,乙醇-细胞比产率以及乙醇-细胞得率分别为0.148 g/(g·h)和77.63 g/g,分别是菌株SO的1.57倍和1.71倍.结果表明,酵母菌在膜生物反应器封闭循环发酵过程中有被定向驯化以适应此发酵环境的可能性,并且野生酵母S3比工业安琪酵母SO更容易被定向驯化.     

碳分子筛填充硅橡胶膜用于渗透蒸发分离稀醋酸-水溶液

From the reference[1] it is known that the addition of silicalite-1 in silicone rubber membranes results in an increase of both flux and selectivity for alcohol in the separation of alcohol/water by pervaporation.In order to enhance performance of pervaporation toward the aqueous solution of acetic acid,incorporation of carbon molecular sieve(CMS)into a PDMS membrane was investigated. CMS is widely used in adsorption processes because of its high selectivity toward certain compounds[2]. It was assumed that the flux and selectivity of pure PDMS membrane could be enhanced owing to the preferential adsorption of CMS to organics.CMS content in the membrane and several important pervaporation operation parameters, including feed concentration of acetic acid, and feed temperature, were investigated.     

用硅橡胶膜生物反应器系统选育高性能酿酒酵母

应用硅橡胶膜生物反应器的发酵-渗透汽化耦合功能,进行长期封闭循环发酵,使酵母在这种特定环境下完成适应性自然进化,从而获得优势的突变株。以工业安琪酵母ADY为原始菌株,进行每一轮500h的封闭循环发酵,在发酵终点取菌悬液做平板筛菌,分离出遗传约200代的相对强势的新菌株,再转移新菌株进行同样的发酵和终点筛选实验。如此的发酵-筛选-转移实验共进行了3轮。试验结果表明:ADY遗传超过600代的菌株S33,在500h封闭循环发酵残液配制的培养基条件下,表现出了明显的环境适应性遗传优势,其细胞生长速率、产物乙醇的比生成速率和糖转化率都相对原种菌ADY分别提高了约71.8%、53.6%和52.7%。     

熔融结晶洗涤分离塔传递行为的数学模型及实验

通过对熔融结晶洗涤分离塔的传递行为进行分析,建立了简化的数学模型,得到了晶层内的压力分布、温度分布和杂质浓度分布表达式。并将理论模型的计算结果和实验结果进行比较,二者吻合较好。